Biodegradable polymers as floating row covers in field production of radish

Abstract

Polypropylene (PP) covers are used in radish (Raphanus sativus L. var. sativus) production to provide better microclimate for improving yield and quality, but disposing of non-degradable covers is difficult and expensive. In this work, nonwovens prepared from biodegradable polymers (aliphatic-aromatic copolyesters with and without fatty acid dimers: SB48/11, SB20/13, SB21/13, SB28/13) were tested in the field as substitutes for nonwoven PP. Minimum air temperature under biodegradable covers was higher by 0.6-0.8 °C than under nonwoven PP, but photosynthetically active radiation (PAR) transmission was lower by 4.1% (SB20/13) and 7.1% (SB21/13). We observed a decrease in marketable yield of plants covered with biodegradable fleeces by 1.01 to 2.90 kg m-2 (SB48/11 and SB28/13, respectively) in spring seasons, but similar yields to nonwoven PP were obtained in the autumn seasons. Dry weight, soluble sugars, L-ascorbic acid, pigments content in radish was dependent on a specific set of environmental conditions rather than on the type of cover. However, L-ascorbic acid content in the roots increased significantly by 6.4 and 2.9 mg 100 g-1 FW for SB48/11 and SB20/13 (in one trial), respectively, as compared to nonwoven PP. It is possible to use biodegradable nonwovens as floating covers for radish cultivated in seasons with temperature drops.